Most of the changes revolve around the sexual assault of Chato's wife and some of the more violent scenes in the film. If Chato's wife is shown mostly clothed or covered during and after the assault then the Blu-Ray contains the US version. If she is shown naked during and after the assault then the Blu-Ray contains the harsher European cut.
I'm a pretty big Bronson fan, but this (for me) is one of the weaker pairings with Michael Winner; when compared to The Mechanic and Death Wish anyway.
My uncut version of Chato's Land off of Encore Westerns runs 100 minutes. It has all the scenes that IMDb says were deleted from various other versions, which I think include the MGM/UA DVD and earlier Encore broadcasts.
Now if only Lawman (1971) could be restored to its uncut version. A couple of early reviews of the film on IMDb and Amazon reference nudity and/or violence that is missing from the MGM/UA DVD and current broadcast versions.